Steam heating system



March 2, 1965' J. a. WRIGHT ETAL STEAM HEATING SYSTEM Original Filed July 28, 1959 4 Sheets-Sheet 1 m w 2%. WW mww m H J r March 1965 J. B. WRIGHT ETAL STEAM HEATING SYSTEM 4 Sheets-Sheet 2 Original Filed July 28, 1959 M Z W n SH 7 a mm mm w Q i. nuhuu 3? fifldll 8 2 7m r L 0..., a .m. w w. M Q & I! If wm L MN NW N\ w f M F w Q\ m m m\ a z: I t 7% t ii a Eh l? ANN A ..1 N m J N n March 1955 J. a. WRIGHT ETAL 3,

STEAM HEATING SYSTEM Original Filed any 28, 1959 4 sheets-sheet 3 I. Q FROM 01mm u k //E'I7'ING ZONE M Ca/vasn snrz (76 Pumps 8 88 E 76 74 86 f n INVENTORS Jhw B. WW4? ATTORNEYS STEAM HEATING SYSTEM 4 Sheets-Sheet 4 Original Filed July 28, 1959 Tlcijwi l fi//// 4 9 6 0 9 m w ME 7,. v m 7i United States Patent 3 Claims. 01. 237-67) This invention relates in general to heating systems and in particular to a new and useful heating system which is divided into a plurality of heating zones each serviced by a separate condensate pump which returns liquid back to the boiler after the air and non-condensable gases have been separated from the liquid and removed, and including a single vacuum pump for servicing the whole system located in the vicinity of the 'boiler and to a method of heating a building by dividing the building into heating zones having individual drain collecting areas and by separately pumping liquid and air from said areas.

This is a continuation application of Serial No. 830,013, filed July 28, 1959, now abandoned.

The present invention is particularly directed to heating systems for use with large area, single story constructions constructed directly on the ground, the so-called slab-on-grade construction, such as a single story school building. Prior to the present invention, with such building constructions the trend has been to the use of a heating system other than a steam heating system because of the difliculties in using steam heating in such constructions. The present day vacuum heating steam system largely employs piping, both supply and return, which is located at elevations below the heating surfaces. When the type of construction employs a basement or other space under the first floor, there is a place for this piping, but wtih the slab-on-grade construction the space is not available. With previous piping systems, the only way to use steam as a heating medium is to install the piping in trenches. These trenches, particularly when they are at the outside walls, are very costly and present structural difliculties.

In accordance with the present invention the individual heating units are arranged to gravity drain to a condensate receiver through lines which are located either above, below or within the slabs, but the remaining portions of the piping may be advantageously located above ground and within the building construction. Such a system includes a steam supply line which is connected to the branch steam supply lines of the individual heating units through a central overhead main steam supply conduit. The system, according to the present invention also includes an air vacuum line which is maintained under vacuum by a single vacuum pump or vacuum pump set located preferably in the boiler room and which eifectively maintains a vaccum on the whole system by a line which extends preferably through a ceiling wall of the building construction. Condensate which is collected in the re ceiver of each of the heating zones of the system is pumped back to the boiler when the condensate within the receiver reaches a predetermined level, and the condensate return line is also located above ground within the building construction.

The present vacuum steam heating system finds particular application in the slab-on-grade school house construction and provides a steam system that is comparable in cost and equal or superior in operating efficiency to the very best type of hot water system. With the improved system according to the invention there is a practical elimination of trenching below the slab as was heretofore necessary. The present system eliminates or only necessitates a minor degree of trenching to accommodate the 3,171,598 Patented Mar. 2, 1965 returns from the heating units to the condensate receiver. Since the trenches heretofore used have been of considerable size, in some cases large enough for a man to crawl through, they have been very expensive and the present construction materially reduces the installation expense of such a system.

A feature of the present invention is that the piping is arranged to give more positive distribution of steam throughout the structure. This results in economy of operation and more stable, and hence, more comfortable conditions within the rooms. The distribution of the steam is improved because of several factors. By the employment of a single vacuum pump or a vacuum pump set to maintain a substantially uniform vacuum condition throughout the vacuum vent line, the air is uniformly removed from the system and the steam is circulated more evenly.

A further feature of the invention is that the return lines from the individualunits to the condensate receiver are relatively short. They are arranged to drain by gravity into the condensate pump receiving tank located Within a given section or zone which is serviced within the building by separate condensate pumps. In these relatively short return lines, it is a relatively easy matter to provide a great degree of pitch so that the lines drain quickly and positively back to the condensate receiver tank. Because the pitch may be made relatively great there is less of a chance for pockets of water to form in the lines which might interfere with drainage. By using what amounts to several small or sectionalized systems of steam heating, it is not necessary to remove all the returns, a mixture of air, non-condensable gases, and Water, through a common return line that extends from one end of the building to the other. Each sectionalized portion of the building is arranged to drain into a condensate receiver unit centrally located within this section.

In accordance with the invention air and water are separated in the condensate pump receiver tanks located in the various zones or modules. After the air and water are separated the water may be pumped as a solid stream and under pressure through lines running from the pump tanks 'back to the boiler. At the same time,

the air is handled through relatively small piping that extends back to the vacuum pump. Such a construction and arrangement permits a material reduction in piping size and the handling of air and water separately.

The system operates without the possibility of detaining any appreciable amount of condensate within the system. With covnventional steam heating systems, it is probable that, because of the long return lines, a

relatively large volume of water will be detained in the piping. This detention of Water within the piping causes a considerable variation in the water level of the boiler due to the periodic detention of the large amounts of water in the piping which may be returned quickly when the pumps are started. The present invention includes very short return lines and the positive drainage in those lines will detain very little water. As soon as a pump starts it will, in effect, put water into the boiler because the pump discharges through a check valve into the line which will be filled with condensate at all times. The condition will obtain in the line all the way back to the boiler. Because there is a minimum of condensate detained in the system it is not necessary to use condensate storage tanks to obviate this condition.

A vacuum heating pump which was employed with previous systems usually included both a water pump ing and an air pumping unit mounted on the same receiver. In the present construction the two pumping functions are entirely divorced and separated from each other, and separate units are located in the system at units in the manner described it is possible to achieve the advantages which have been outlined herein.

Accordingly, it is an object of this invention to provide an improved steam heating'system.

A further object of this invention is to provide a steam heating system having a plurality of heating zones and having piping from a boiler to supply steam to the heating units in each zone from pipes located above ground and within the walls of the structure, and further having a condensate receiver and a condensate pumping unit located in each of the heating zones to receive condensate from the heating units and arranged to pump condensate directly backto the boiler after the air has been separated therefrom, and further having a single vacuum pump or a set of vacuum pumps usually located adjacent the boiler which serves all of the heating zones to maintain substantially uniform vacuum throughout the system.

A further object of this invention is to provide a steam heating system which is simple in design, rugged in construction and economical to manufacture and install.

. ,The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part'of this specification. For

a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

In the drawings:

FIG. 1 is a schematic perspective view of a portion of 'a school building employing a heating system constructed in accordance with the invention;

FIG. 2 is a fragmentary transverse section through a portion of the building employing the heating system constructed in accordance with the invention;

FIG. 3 is a horizontal section taken on the line 33 of FIG. 2;

FIG. 4 is a fragmentary longitudinal section of a portion of the boiler room and adjacent heating zone having a heating system constructed in accordance with the invention;

FIG. .5 is a view similar to FIG. 4 of a somewhat modified form of another embodiment of heating system;

FIG. 6 is a fragmentary transverse section through a portion of a building indicating another embodiment of heating zone condensate unit; and

FIG. 7 is a horizontal section taken on the line 7-7 of FIG. 6.

Referring to the drawings in particular the invention is embodied therein in association with a school building generally designated 10 which is a single story struc ture spread over a considerable area and constructed directly on the ground as a socalled slab-ongrade construction. The school building 10 includes a slab floor 12 outside walls 14 and 16 and central corridor walls 18 and 20 which extend .substantially along the entire length of the building.

In accordance with the invention a plurality of radiator heating units 19 such as the eight units indicated in FIG. 1 are isolated in a separate heating zone or module. One or more of the radiator heating units 19 are advantageously arranged in a separate room, such as a classroom, and each is supplied from a boiler or other steam supply source (not shown) with steam transmitted through a main steam line 21 which extends along the length of the corridor of the building and is located within or adjacent the ceiling thereof. Each zone or module .is fed from laterally extending steam line branches 22 and 24 which supply steam through a series of connections to the individual radiator units 19.

Each of the radiator steam units 19 is arranged to drain through return lines 26, at least a portion of which are located in trenches beneath the slab 12 and are pitched downwardly into a condensate receiver tank 28 located within a condensate pump pit 30. It should be appreciated that in some instances the radiator units 19 may be located at elevated positions permitting drainage to a receptacle located above floor level and not necessarily in a pit as in the present case. he pit 3% in the present instance is located within a recessed portion beneath service closets 31 at central locations throughout the building to service as many of the zones as are provided in the building. It should be appreciated that while the condensate pump pit 30 includes pumping units to service eight radiator units 19 in the present embodiment, that other variations of the number and arrangements of units may be had within the scope of the invention.

In accordance with the embodiment illustrated in FIGS. 1 to 3 the condensate receiver tank is provided with means for separating the condensate from the air and non-condensable gases of the system and for allowing the liquid condensate to fill up in the tank to a predetermined level. Afiixed to each side of the condensate tank is a centrifugal condensate pump 32 and 34, respectively, which are arranged in 'a side wall of the tank to take the suction directly from the tank and discharge it through a boiler return feed line 36 which extends upwardly in the service closet 31 and connects to a main boiler feed return line 38 which extends the length of the building above the corridor 37 and back to the boiler (not shown). The pump 32 is arranged to feed through a check valve 39, a valve 40 and conduit 42 to the boiler feed return 36, while the pump 34 discharges through a valve 44 directly into the boiler feed return 36. The boiler feed return 36 is maintained full of liquid so that operation of any one of the pumps in a heating zone will effect immediate pumping of liquid to the boiler. One of the pumps 32 and 34 normally functions as a standby. Instead of a duplex pump system a single pump may be connected to the tank 28 and extend outwardly in either the side or the top. Air is continuously vented from the receiver 28 through a vacuum vent line 46 which'connects through a riser 43 to a main vacuum vent line 50. The main vacuum vent line 5% extends substantially the complete length of the building and back to a boiler room 52 as indicated in FIG; 4.

In the boiler room is located a single liquid ring vacuum pump '54 which is arranged to maintain a vacuum on the complete system. The vacuum pump 54 receives water sealing liquid preferably through a conduit 56 which is supplied through a constant flow valve 58 and a solenoid valve 60 and a vacuum break 62 and feeds into a constant level supply tank 64. The pump 54 is arranged to discharge into the constant level cold water seal supply tank 64 and then to the atmosphere through the. upper end thereof through a silencer 66. Excess liquid in the tank 64 drains through a drain conduit 68.

In the embodiment illustrated in FIG. 5 a single condensate pump 7 0 is associated with a receiver 72 to service a given heating zone. It should be appreciated that either a single for a duplex pumping unit may be located in the pit 30 and the number and sizing thereof would depend on the number of zone heating units which is to be serviced thereby. Condensate is returned through check valve 73 into a riser 74 by the pump 70 back to a boiler'Qnot shown). The riser joins a main condensate return line 76. which receives condensate from other heating zones and returns it back to the boiler.

. Air is continuously vented from the reservoir tank -72 through a vacuum vent line 78 which feeds through a main vacuum 'vent line 80 which connects into the other heating zones. The line 80 in the present embodiment connects to a control tank 82 which drains directly to a vacuum pump 84, the latter discharging through a discharge tank 86 and being vented to the atmosphere through a silencer 38. The tank 82 drains into the pump 4 84 and the liquid does not interfere with the pump operation.

In each of these systems the vacuum pump 84 is controlled by suitable controls (not shown) which regulate the pump in accordance with temperature conditions and conditions at each reservoir tank in each heating zone. The condensate pumps are operated in accordance with the level of the liquid in the condensate receivers 23 and 72 as controlled by a float valve (not shown) located within each tank.

In the embodiments indicated in FIGS. 6 and 7 there is provided the usual receiver tank 90 which is arranged to receive condensate, air and non-condensable gases through a gravity return line 92 which connects to the various heating units (not shown). In this embodiment a condensate pump 94 is mounted above the receiver tank 90 and is arranged to discharge through a check valve 96 and a gate valve 98 to a boiler feed return line 100. A vacuum vent line 102 extends from the receiver tank 90 back through a line connecting the inlet of a vacuum pump (not shown). By locating the condensate pump 94 above the receiver tank 90 it is possible to locate the complete unit within a small sized pit 104. The use of a vertical type pump permits a reduction in the size and depth of the pit and in some instances even the elimination of the pit. Such latter instances would occur when the heating units are at a sufiicient elevation to permit gravitational draining through the line 92 to a receiver 9% which can be located above ground.

Thus, the invention provides an improved heating system in which Various heating zones may be regulated independently and in which the steam is evenly distributed to the various zones and to each of the heating units within each zone. By dividing the system into heating zone units, serviced by one or more condensate pumps, it is possible to use a single vacuum pumping unit to regulate the return line vacuum on the complete system of a plurality of zones. The arrangement permits economy of piping and a severe reduction in the installation cost. Since most, if not all, of the piping may be located above ground, it is not necessary to run expensive and elaborate trenches throughout the building length.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the invention principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

We claim:

1. In combination a single story building and a steam heating system for said building; said building being of the slab-on-grade type and including a foundation slab substantially coplanar with the surrounding ground level and a ceiling spaced above said slab; said steam heating system comprising, a plurality of individual heating units spaced throughout said building at a level closely adjacent the level of said slab, a steam supply main extending within said building at substantially the level of said ceiling, means connecting said steam supply main to each of said heating units, said heating units being grouped no a plurality of return line zones, a condensate receiver for each of said return line zones, said receiver being recessed in said building slab and being located substantially central within each of said return line zones, downwardly pitched conduit means connecting the heating units in each return line zone to its respective condensate receiver, a condensate pump directly affixed to each condensate receiver to draw condensate from a lower portion of said receiver, a main condensate return line at substantially the ceiling level of the building, conduit means between said main condensate return line and the discharge of each condensate pump, a main vacuum vent line to the ceiling level of said building and conduit means connecting said vent line to an upper portion of each condensate receiver.

2. The combination of claim 1 including check valve means in each of said conduit means between said main condensate return line and the discharge of said condensate pumps to prevent flow back of condensate to said pumps.

3. In combination, a single story building and a steam heating system for said building, said building being of the slab-on-grade type and including a foundation slab substantially coplanar with the surrounding grade level, a plurality of walls, and a ceiling spaced above said slab and supported by said walls; said steam heating system comprising, a plurality of heating units spaced throughout said building at a level closely adjacent the level of said slab, a steam supply main extending throughout said building at substantially ceiling level, downwardly extending conduit means connecting said steam supply main to each of said heating units, said heating units being grouped into a plurality of return line zones, a condensate receiver for each of said return line zones, said receiver being recessed in said building slab and being located substantially central within each of said return line zones, condensate drain means connecting each of said heating units in each return line zone to its respective condensate receiver, a main condensate return line located at substantially the ceiling level of said building, a pair of con densate pumps directly aflixed to each condensate receiver to draw condensate from a lower portion of said receiver and discharge it upwardly therefrom through conduit means to said main condensate return line, a main vacuum vent line located at substantially the ceiling level of said building, a main vacuum pump for evacuating said main vacuum vent line and conduit means connecting said main vacuum vent line to an upper portion of the receiver associated with each of said return line zones whereby the condensate drain means in each of said return line zones are at substantially the same vacuum.

References Cited in the file of this patent UNITED STATES PATENTS 1,024,547 Ball Apr. 30, 1912 1,984,290 Stout Dec. 11, 1934 3,064,901 Viner Nov, 20, 1962, 

1. IN COMBINATION A SINGLE STORY BUILDING AND A STEAM HEATING SYSTEM FOR SAID BUILDING; SAID BUILDING BEING OF THE SLAB-ON-GRADE TYPE AND INCLUDING A FOUNDATION SLAB SUBSTANTIALLY COPLANAR WITH THE SURROUNDING GROUND LEVEL AND A CEILING SPACED ABOVE SAID SLAB; SAID STEAM HEATING SYSTEM COMPRISING, A PLURALITY OF INDIVIDUAL HEATING UNITS SPACED THROUGHOUT SAID BUILDING AT A LEVEL CLOSELY ADJACENT THE LEVEL OF SAID SLAB, A STEAM SUPPLY MAIN EXTENDING WITHIN SAID BUILDING AT SUBSTANTIALLY THE LEVEL OF SAID CEILING, MEANS CONNECTING SAID STEAM SUPPLY MAIN TO EACH OF SAID HEATING UNITS, SAID HEATING UNITS BEING GROUPED INTO A PLURALITY OF RETURN LINE ZONES, A CONDENSATE RECEIVER FOR EACH OF SAID RETURN LINE ZONES, SAID RECEIVER BEING RECESSES IN SAID BUILDING SLAB AND BEING LOCATED SUBSTANTIALLY CENTRAL WITHIN EACH OF SAID RETURN LINE ZONES, DOWNWARDLY PITCHED CONDUIT MEANS CONNECTING THE HEATING UNITS IN EACH RETURN LINE ZONE TO ITS RESPECTIVE CONDENSATE RECEIVER, A CONDENSATE PUMP DIRECTLY AFFIXED TO EACH CONDENSATE RECEIVER TO DRAW CONDENSATE FROM A LOWER PORTION OF SAID RECEIVER, A MAIN CONDENSATE RETURN LINE AT SUBSTANTIALLY THE CEILING LEVEL OF THE BUILDING, CONDUIT MEANS BETWEEN SAID MAIN CONDENSATE RETURN LINE AND THE DISCHARGE OF EACH CONDENSATE PUMP, A MAIN VACUUM VENT LINE TO THE CEILING LEVEL OF SAID BUILDING AND CONDUIT MEANS CONNECTING SAID VENT LINE TO AN UPPER PORTION OF EACH CONDENSATE RECEIVER. 